The present disclosure relates to the field of motor vehicle brakes. Stated more precisely, the disclosure relates to a subassembly of a brake actuator, for example for an electromechanically operated parking brake or an electromechanically operated service brake.
Electrically operated parking brakes (EPB) more and more frequently replace conventional parking brakes, which convert a force applied by the driver by way of pulleys into a clamping force at wheel brakes of the vehicle. The advantage of electrical parking brakes lies in their ability to be controlled by means of modern on-board electronics. In this way, new application possibilities for the parking brake open up, such as, for example, the implementation of an aid for starting on a hill (hill hold function).
An electrically operated parking brake generally comprises an electromechanical brake actuator, which exerts a clamping force on the wheel brakes by way of a mechanically displaceable brake piston. The brake actuator is essentially defined by a subassembly composed of drive devices and gear mechanisms, which are mounted in a housing in damping manner. To increase the performance capacity, a multi-stage gear mechanism is frequently used in this regard, in order to achieve strong gear reduction of the rotation movement generated by the electric motor.
A particular challenge now consists in designing a high-performance, low-wear and, at the same time, spatially compact electromechanical brake actuator. In particular, the brake actuator must be suitable for installation in the space conditions in the region of a vehicle wheel, which are typically restricted. In this regard, the dimensions of the available installation space can depend on numerous further adjacent vehicle components and can vary greatly, depending in the vehicle variant.
Electromechanical brake actuators having a subassembly are known from the patent applications DE 10 2004 048 700 A1 and DE 10 2010 032 053 A1, which actuators have a three-stage gear mechanism. The gear mechanism comprises two consecutive gear wheel gear stages, in each instance, followed on the output side by a planetary gear set stage.
It has been shown that such brake actuators are not suitable for all installation situations and prevailing space conditions.